DeLaet was born in Weyburn, Saskatchewan and grew up there and in Moose Jaw. He attended Boise State University where he won 10 collegiate tournaments. He was on the Canadian development golf team, organized by the RCGA, from 2005 to 2006, and credited this experience with improving his game. DeLaet finished 2nd as an amateur in the 2005 Edmonton Open, a Canadian Tour event.

DeLaet turned professional in 2007 and played on the Canadian Tour that year. In his 2007 rookie season he made 11 of 14 cuts with seven top-10 finishes. He was awarded the Bob Beauchemin Shield as the Canadian Rookie of the Year.

He got off to a slow start in 2008, in which he missed the cut in five of his first eight events. However, he earned his first victory as a professional in his ninth start of the season at the Desjardins Montreal Open in a playoff, earning the first place prize of $32,000. He followed this up with a 2nd-place finish at the Jane Rogers Championship the following week and finished tied for 2nd at the season ending Tour Championship.

2009 was a successful season for DeLaet in which he spent time playing on the South African-based Sunshine Tour and the Canadian Tour. During the Canadian Tour season he had two victories at the ATB Financial Classic and the Players Cup and six top-10 finishes in only nine events played. He amassed earnings of $94,579 to lead the Canadian Tour Order of Merit and was chosen as the Player of the Year. At the end of the Canadian Tour season, he rejoined the Sunshine Tour and earned his third victory of the year at the BMG Classic. He finished 8th on the 2009 Sunshine Tour order of Merit while competing in only 5 tournaments and earned R 861,323.

DeLaet also played in one Nationwide Tour event in 2009, placing T31 at the Ford Wayne Gretzky Classic, with a score of 279 (6-under-par). He played in the 2009 RBC Canadian Open on the PGA Tour, placing T46 with a score of 282 (6-under-par).

DeLaet represented Canada with Wes Heffernan at the 2008 Omega Mission Hills World Cup. In 2009, he played alongside Stuart Anderson.

In 2010, after top-25 finishes in his first two events followed by five missed cuts, DeLaet had his best ever finish at the Shell Houston Open, finishing T-3, one stroke out of the playoff between Vaughn Taylor and Anthony Kim. He had his second top-10 finish of the 2010 season in October at the Viking Classic, with a T-5. The next week, DeLaet finished T-25 at the McGladrey Classic, his sixth top-25 finish of the season. He had his third top-10 finish of the season the next week with a T-6 at the Frys.com Open. The finish secured DeLaet his tour card for the 2011 PGA Tour season.

DeLaet played the 2012 season on a Major Medical Exemption with 26 starts to make $657,694 and match D. J. Trahan, the golfer who placed 125th on the 2011 money list. At the Sony Open in Hawaii, the first full-field event of the season, DeLaet led the first round in his first Tour event since June 2011. He finished fourth at the Zurich Classic of New Orleans, his best finish of the season. DeLaet satisfied the terms of his exemption in July 2012 with eight starts to spare and kept his Tour card.

In 2016, DeLaet qualified for the 2016 Summer Olympics in Rio de Janeiro, marking golf’s return to the Olympics for the first time since the 1904 Summer Olympics in St. Louis. DeLaet represented Canada. Canada was the defending nation of men’s golf at the Olympics as George Lyon won gold in 1904. As DeLaet represented the defending champion nation he was in the first group to tee off at the tournament. Shortly before the games began, his caddie decided to not participate, prompting DeLaet to pick the recently retired NHL player Ray Whitney as his new caddie. DeLaet shot a 66 (5-under-par) in the first Olympic round ever on 11 August 2016, including 6 birdies and 1 bogey. He finished the tournament in 20th place.